1. The Field of the Invention
This disclosure describes apparatus, means, and systems for tying down a cover for a compost pile. The disclosure also describes methods of using the described apparatus, means, and systems for tying down a cover for a compost pile.
2. The Relevant Technology
Composting of feedstock waste materials is gaining popularity on a global scale to minimize waste products going to landfills, reduce green house gas emissions from uncontrolled decomposition of organics, and to create useable compost end-products which are used to restore nutrients, tilth, and water-holding capacity to depleted soils. Common waste feedstock materials include green wastes, food wastes, and animal manures. The composting process produces foul odors as the biodegradation of the wastes proceeds, which prompts many compost operators to either locate their operations in locations remote from populated areas or to enclose their operations to capture and treat the odor emissions.
Building enclosures have been employed, but are expensive to construct and require air exchange and external “scrubbing” facilities to remove odors. The advent of selectively porous laminate textile fabrics (such as the trademarked GORETEX fabric) has offered an alternative for covering compost piles that effectively sequesters the large-molecule odorous compounds beneath the cover while allowing oxygen and CO2 exchange, which is vital to the composting process. The covers provide a cost-effective alternative to construction of building enclosures and separate odor treatment systems, allowing for composting nearer to population centers where the feedstock wastes are generated.
Fabric covers are deployed over large compost windrows (typically 100-150 feet in length, 20-30 feet in width, and 6-12 feet in height) which overlie aeration plenums that extend beneath the windrow length and provide pumped air (e.g., via blower) up and through the windrow. The air supply provides oxygen, which is critical to the composting process, and drives off CO2, which passes through the cover to atmosphere. Water and odorous compounds are selectively retained beneath the cover where the water contributes to efficient composting. And the odorous compounds are destroyed by the on-going composting process.
The fabric covers, while cost competitive with other enclosure systems, are often expensive and are typically required to meet air permeability and minimal tear-strength, puncture-resistance, and UV resistance characteristics.
When deployed, the covers are exposed to the elements. And the greatest physical threat to a properly fabricated cover is wind dislocation after deployment. In addition, excessive blower discharge through the air plenum can exceed the air permeability of the cover, resulting in excess odorous air escape beneath the perimeter of the deployed cover. To combat these two issues, cover manufacturers have developed cover anchorage schemes.
For example, in order to anchor a compost cover, manufacturers and composting facilities (1) use a continuous flexible hose (4-6 inch diameter), typically filled with water, sand, or other heavy material, around the cover perimeter, (2) use continuous, joined, heavy steel pipe sections around the cover perimeter, (3) place heavy feedstock, finished product, soil, or other aggregate material continuously around the cover perimeter, (4) place concrete parking stops intermittently around the cover perimeter, or (5) place “super sack” bags of feedstock or finished product, intermittently around the cover perimeter.
All of the foregoing anchorage schemes rely on the weight or mass of the anchorage system around the cover perimeter to hold the cover in position and to seal the perimeter from air escape. Such strategies must employ either heavy equipment or multiple personnel, or both to effectively place and remove the anchorage system because the components of the foregoing anchorage systems are often too bulky or heavy for one person to move. And those strategies using water as the mass are subject to leaking and, in cold climates, freezing. The anchorage schemes using loose aggregate materials require cleanup sweeping upon removal. And all the “heavy mass” anchorage strategies risk damage to the cover during placement and removal.
Another anchorage scheme that has been employed is the use of a net “webbing” over the entire pile, which is anchored to the ground around the perimeter of the pile. However, this type of scheme involves intermittent anchor placement, which may result in gaps to the sealing of the cover perimeter, allowing odorous air to escape under excess blower discharge conditions.
Since compost covers started to be used, over a decade ago, compost cover anchorage, or tie-down, systems have failed to provide methods and systems for securing compost covers to prevent the release of odorous compounds without the use for heavy-weight components.